CN113613972B

CN113613972B - Air supply system

Info

Publication number: CN113613972B
Application number: CN201980092997.9A
Authority: CN
Inventors: 杉尾卓也
Original assignee: Nabtesco Automotive Corp
Current assignee: Nabtesco Automotive Corp
Priority date: 2018-12-28
Filing date: 2019-12-27
Publication date: 2024-03-29
Anticipated expiration: 2039-12-27
Also published as: WO2020138391A1; EP3904169B1; EP3904169A1; JPWO2020138391A1; JP7420740B2; JP2024026707A; CN113613972A; EP3904169A4

Abstract

Provided is an air supply system capable of improving the combustion consumption rate involved in driving a compressor. The air supply system performs a supply operation of supplying compressed air supplied from the compressor (4) from an upstream to a downstream via an air dryer (11) having a filter (17) and a check valve (19). The air supply system is provided with an ECU (80), wherein the ECU (80) switches between a supply operation performed when the supply start value is less than or equal to the supply stop value and a non-supply operation performed when the supply stop value is greater than or equal to the supply stop value and in which compressed air is not supplied downstream of the check valve (19), and performs a regeneration operation for regenerating the filter (17) during the non-supply operation. The ECU (80) executes regenerative supply when conditions including no regeneration operation, a detected air pressure being higher than a supply start value and lower than a supply stop value, and the engine being in no-load operation are satisfied.

Description

Air supply system

Technical Field

The present invention relates to an air supply system for supplying compressed air to an apparatus.

Background

In vehicles such as trucks, buses, and construction machines, an air pressure system including a brake, a suspension, and the like is controlled by compressed air sent from a compressor. The compressed air contains moisture contained in the atmosphere and liquid impurities such as oil for lubricating the inside of the compressor. If compressed air containing a large amount of water and oil enters the air pressure system, rust and swelling of the rubber member may occur, which may cause a failure in operation. Therefore, an air dryer for removing impurities such as moisture and oil in the compressed air is provided downstream of the compressor.

The air dryer performs a dehumidifying operation for removing oil and moisture from compressed air and a regenerating operation for removing oil and moisture adsorbed to a desiccant from the desiccant and discharging the oil and moisture as a drain. For example, patent document 1 describes a technique for performing a regenerating operation in an air dryer.

The air supply system described in patent document 1 stores air compressed by an air compressor in a gas tank. When the air pressure in the air tank is equal to or lower than the first pressure, the air supply system drives the air compressor to supply compressed air to the air tank until the air pressure rises to reach the second pressure. When the air pressure reaches the second pressure, the air supply system stops the supply of compressed air from the air compressor to the air tank, and opens the discharge valve (purge valve). After that, the air supply system performs the following regeneration operation until the air pressure drops to the third pressure: the compressed air in the air tank is discharged to the atmosphere after passing through the air dryer by maintaining the valve-opening state. When the air pressure in the air tank reaches the third pressure, the air supply system closes the discharge valve.

Prior art literature

Patent literature

Patent document 1: japanese patent application laid-open No. 2015-229127

Disclosure of Invention

Problems to be solved by the invention

In the air supply system described in patent document 1, the air dryer is regenerated by compressed air in the air tank.

In recent years, the following techniques for retrogradation supply are known: in order to reduce the engine load involved in driving the compressor, the compressor is driven by the rotation of the engine at the time of no-load operation such as the time of no-fuel injection of the engine, which is the timing when the rotation of the engine is not used for running. However, the start condition of the regeneration supply is related to the vehicle state, while the start condition of the regeneration operation is related to the air pressure. Therefore, both of the start conditions may be satisfied. When both of the start conditions are satisfied, the regeneration operation and the regeneration supply are performed simultaneously. In this case, there is a risk that the regeneration-supplied compressed air is discharged and the effect of reducing the engine load is lost, or there is a risk that the regeneration time of the air dryer does not reach a predetermined value and sufficient regeneration cannot be performed, and thus a regeneration failure of the air dryer occurs. That is, there is room for improvement in adjusting the execution timing of the regeneration operation and the regeneration supply.

The purpose of the present invention is to provide an air supply system that can achieve an increase in the combustion consumption rate associated with the driving of a compressor.

Solution for solving the problem

An air supply system for achieving the above object performs a supply operation of supplying compressed air supplied from a compressor from an upstream side to a downstream side through an air dryer having a filter and a check valve, the air supply system comprising: a pressure sensor that detects an air pressure downstream of the check valve; and a control device that switches between the supply operation and a non-supply operation, and performs a regeneration operation that regenerates the filter in the non-supply operation, wherein the control device is provided with a supply start value for starting the supply operation based on a comparison of the supply start value and a detected air pressure detected by the pressure sensor, and a supply stop value that is higher than the supply start value for starting the non-supply operation based on a comparison of the supply stop value and the detected air pressure, and performs the supply operation by regenerating a supply when a condition including: the regeneration action is not performed; the detected air pressure is higher than the supply start value and lower than the supply stop value; and the engine driving the compressor is in no-load operation.

In this case, when the vehicle is in a no-load operation in which the engine is driven by rotation of the wheels during deceleration, regenerative supply is performed in which compressed air is supplied by driving the compressor by rotation of the engine. The regeneration supply is performed before the supply of the compressed air by the normal supply operation, and the supply of the compressed air by the normal supply operation is supplemented. In addition, in the regeneration supply, fuel consumption for driving the compressor does not occur in the engine, so that the combustion consumption rate of the engine can be improved. Therefore, the combustion consumption rate related to the driving of the compressor can be improved.

In one embodiment, the no-load operation of the engine may include no-fuel injection of the engine.

In this case, when the engine is in the fuel-free injection, the rotation of the engine is effectively utilized for the air supply.

In one embodiment, the control device may cause the retrograde feed to last for 10 seconds or more.

In this case, when the compressor is switched from the no-load operation to the load operation, occurrence of timing when compressed air is not supplied due to a delay in supply of compressed air can be avoided.

In one embodiment, the condition may further include that the detected air pressure is equal to or lower than a predetermined air pressure.

In this case, when the compressor is switched from the no-load operation to the load operation, the occurrence of timing when the compressed air is not supplied due to a delay in the supply of the compressed air can be suppressed.

In one embodiment, the control device may not start the regeneration supply when the regeneration operation is being performed.

In this case, the regenerating operation does not become wasteful due to the regenerative supply. In addition, the regeneration performance is not reduced due to the interruption of the regeneration operation caused by the regeneration supply.

In one embodiment, the control device may acquire a case where the engine is in no-load operation from a control device of the vehicle.

In this case, the engine can be acquired from the control device of the vehicle as being in no-load operation.

Drawings

Fig. 1 is a block diagram showing a schematic configuration of an embodiment of an air supply system used in an air brake system.

Fig. 2 is a schematic configuration diagram showing the air supply system according to this embodiment.

Fig. 3 is a diagram showing an operation mode of the air dryer according to this embodiment, (a) is a diagram showing a supply operation, (b) is a diagram showing a purge operation, and (c) is a diagram showing a regeneration operation.

Fig. 4 is a graph showing timings of performing a regenerating operation or the like according to this embodiment.

Fig. 5 is a flowchart showing a procedure of performing the regeneration operation of this embodiment.

Fig. 6 is a flowchart showing a procedure of performing the regeneration operation of this embodiment.

Fig. 7 is a flowchart showing a procedure of performing the regeneration operation of this embodiment.

Fig. 8 is a flowchart showing a procedure of performing the regeneration operation of this embodiment.

Fig. 9 is a flowchart showing a procedure of performing the regeneration operation of this embodiment.

Fig. 10 is a flowchart showing a procedure of performing the regeneration operation of this embodiment.

Fig. 11 is a flowchart showing a procedure of performing the regeneration operation of this embodiment.

Detailed Description

An embodiment of an air supply system included in an air pressure system is described with reference to fig. 1 to 4. The air supply system is mounted on an automobile such as a truck, a bus, or a construction machine.

An outline of the air pressure system will be described with reference to fig. 1.

In the air pressure system, the compressor 4, the air dryer 11, the protection valve 12, the air tank 13, the brake valve 14, and the brake chamber 15 are connected in this order via the air supply paths 4E, 11E, 12E, 13E, 14E. The compressor 4, the air dryer 11 and the protection valve 12 constitute an air supply system 10.

The compressor 4 is driven by power of an engine (not shown) of the vehicle, compresses air, and supplies the compressed air to the air supply system 10. The compressor 4 is connected to the air dryer 11 via an air supply path 4E.

In the air dryer 11, the air sent from the compressor 4 is passed through a filter 17 (see fig. 2), whereby impurities in the air are captured and the air is purified. The air thus purified is supplied from the air dryer 11 to the air tank 13 via the air supply path 11E, the protection valve 12, and the air supply path 12E.

The air tank 13 is connected to a brake valve 14 operated by the driver via an air supply path 13E. The brake valve 14 is connected to the brake chamber 15 via an air supply path 14E. Accordingly, in response to the operation of the brake valve 14, air is supplied to the brake chamber 15, whereby the service brake is operated.

The air supply system 10 further includes an ECU 80 as a control device. ECU 80 is electrically connected to air dryer 11 via wirings E62, E63. In addition, ECU 80 is electrically connected to pressure sensor 65 via wiring E65. The ECU 80 detects the air pressure of the protection valve 12 through the pressure sensor 65. A detected air pressure corresponding to the air pressure of the air tank 13 is obtained from the detection signal of the pressure sensor 65. The ECU 80 is connected to the temperature and humidity sensor 66 via a wiring E66. The ECU 80 detects the humidity of the compressed air in the air tank 13 through the temperature and humidity sensor 66. The ECU 80 is electrically connected to the vehicle ECU 100 so that various signals of the vehicle on which the air supply system 10 is mounted can be acquired.

The ECU 80 includes an unillustrated arithmetic unit, a volatile memory unit, and a nonvolatile memory unit, and supplies signals for designating various operations, etc. to the air dryer 11 in accordance with a program stored in the nonvolatile memory unit. The ECU 80 also has a timer for measuring a period of time involved in the regenerating operation.

The air supply system 10 is described with reference to fig. 2.

The air dryer 11 has a maintenance port P12. The maintenance port P12 is a port for supplying air upstream of the filter 17 of the air dryer 11 at the time of maintenance.

ECU 80 is electrically connected to regeneration control valve 21 of air dryer 11 via line E63, and is electrically connected to regulator 26 of air dryer 11 via line E62.

When referring to fig. 3, the inner space 11A of the air dryer 11 is provided with a filter 17. The filter 17 is provided midway in the air supply passage 18, and the air supply passage 18 connects the air supply passage 4E from the upstream compressor 4 to the air supply passage 11E connected to the downstream protection valve 12.

The filter 17 accommodates a desiccant and includes a filter unit. The filter 17 passes the air through the desiccant, thereby removing moisture contained in the air from the air to thereby dry the air, and also removes oil contained in the air from the air through the filter portion to purify the air. The air having passed through the filter 17 is supplied to the protection valve 12 via a one-way valve 19 as a check valve that allows only the air to flow downstream of the filter 17. That is, when the filter 17 is set upstream and the protection valve 12 is set downstream, the check valve 19 allows only air to flow from upstream to downstream.

When referring back to fig. 2, a bypass flow path 20 bypassing (bypassing) the check valve 19 is provided in parallel with the check valve 19 in the check valve 19. The regeneration control valve 21 is connected to the bypass flow path 20.

The regeneration control valve 21 is a solenoid valve controlled by the ECU 80.ECU 80 switches the operation of regeneration control valve 21 by controlling on/off (driving/non-driving) of the power supply of regeneration control valve 21 via wiring E63. The regeneration control valve 21 closes the bypass passage 20 in a state where the power supply is turned off, and opens the bypass passage 20 in a state where the power supply is turned on. For example, the regeneration control valve 21 is driven when the value of the detected air pressure exceeds the supply stop value.

An orifice 22 is provided in a portion between the regeneration control valve 21 and the filter 17 in the bypass flow path 20. When the regeneration control valve 21 is energized, the compressed air in the air tank 13 is sent to the filter 17 through the protection valve 12 and then through the bypass flow path 20 in a state where the flow rate is restricted by the orifice 22. The compressed air supplied to the filter 17 is reversed in the filter 17 from downstream toward upstream. Such a process is a process of regenerating the filter 17, and is called an air dryer regeneration process. At this time, the dried and purified compressed air in the air tank 13 flows back through the filter 17, thereby removing the moisture and the oil captured by the filter 17 from the filter 17. For example, the regeneration control valve 21 is controlled to be opened for a predetermined period. The predetermined period is a period during which the filter 17 can be regenerated, and is set theoretically, experimentally, or empirically.

The branch passage 16 branches off from a portion between the compressor 4 and the filter 17. The branch passage 16 is provided with a drain discharge valve 25, and a drain discharge port 27 is connected to the end of the branch passage 16.

The drain containing the water and oil removed from the filter 17 is sent to the drain discharge valve 25 together with the compressed air. The drain discharge valve 25 is an air pressure driven valve driven by air pressure, and is provided in a portion between the filter 17 and the drain discharge port 27 in the branch passage 16. The drain valve 25 is a two-position two-way valve whose position is changed between a valve-closing position and a valve-opening position. When the drain discharge valve 25 is in the valve-open position, the drain is sent to the drain outlet 27. The drain discharged from the drain outlet 27 may be recovered by an oil separator, not shown.

The drain valve 25 is controlled by a regulator 26. Regulator 26 is a solenoid valve controlled by ECU 80. The ECU 80 controls on/off (driving/non-driving) of the power supply of the regulator 26 via the wiring E62, thereby switching the operation of the regulator 26. When the power supply is turned on, the regulator 26 inputs an unloading signal of a predetermined air pressure to the drain valve 25, and opens the drain valve 25. When the power supply is turned off, the regulator 26 does not input an unloading signal to the drain discharge valve 25, and opens the port of the drain discharge valve 25 to the atmospheric pressure, thereby closing the drain discharge valve 25.

The drain discharge valve 25 is maintained in the closed valve position in a state where the unloading signal is not input from the regulator 26, and is switched to the open valve position when the unloading signal is input from the regulator 26. When the input port of the drain discharge valve 25 connected to the compressor 4 exceeds the upper limit value and becomes high pressure, the drain discharge valve 25 is forcibly switched to the valve opening position.

The compressor 4 performs a load operation for supplying compressed air and a no-load operation for not supplying compressed air. The regulator 26 controls switching between the load operation and the no-load operation of the compressor 4. When the power supply is turned on, the regulator 26 sends an unloading signal to the compressor 4, thereby operating the compressor 4 without load. When the power supply is turned off, the regulator 26 does not input an unloading signal to the compressor 4, and opens the port of the compressor 4 to the atmosphere, thereby operating the compressor 4 under load.

The ECU 80 turns on (drives) the power supply of the regulator 26 based on the detected air pressure of the pressure sensor 65, thereby switching the regulator 26 to the supply position that outputs the unloading signal. In addition, the ECU 80 cuts off (does not drive) the power supply to the regulator 26 based on the detected air pressure of the pressure sensor 65, thereby switching the regulator 26 to the non-supply position at which the unloading signal is not output.

The supply operation, purge operation, and regeneration operation of the air dryer 11 will be described with reference to fig. 3. The supply operation is an operation of supplying compressed air to the air tank 13. The purge operation is an operation to stop the compressor to perform purge processing or the like. The regenerating operation is an operation of causing the filter 17 to perform a regenerating process. The regeneration operation and the purge operation constitute a non-supply operation.

Referring to fig. 3 (a), during the supply operation, ECU 80 CLOSEs regeneration control valve 21 and regulator 26 (referred to as "CLOSE" in the figure). At this time, the drive signal (power supply) from the ECU 80 is not supplied to the regeneration control valve 21 and the regulator 26, respectively. Therefore, the regulator 26 opens the port of the compressor 4 connected downstream and the port of the drain discharge valve 25 to the atmosphere. In the supply operation, the compressor 4 supplies compressed air (shown as "ON"). The compressed air (shown as "IN") supplied to the air dryer 11 is supplied to the air tank 13 (shown as "OUT") via the protection valve 12 after the moisture and oil are removed by the filter 17.

Referring to fig. 3 (b), during the purge operation, ECU 80 closes regeneration control valve 21 and OPENs regulator 26 (referred to as "OPEN" in the figure). At this time, the regulator 26 is opened by being supplied with a drive signal (power supply) from the ECU 80, and the port of the compressor 4 connected downstream and the port of the drain discharge valve 25 are connected to the upstream (protection valve 12), respectively. In the purge operation, the compressor 4 is in a no-load operation state (shown as "OFF") due to an unloading signal (shown as "CONT") from the regulator 26, and the compressed air in the filter 17 and the air supply passage 18 is discharged from the drain outlet 27 together with moisture, oil, and the like.

Referring to fig. 3 (c), in the regeneration operation, ECU 80 opens regeneration control valve 21 and regulator 26, respectively. At this time, a drive signal (power supply) from the ECU 80 is supplied to the regeneration control valve 21 and the regulator 26. In the regenerating operation, the compressor 4 is in the no-load operation state due to the unloading signal from the regulator 26. In the regeneration operation, the regeneration control valve 21 and the drain discharge valve 25 are opened, whereby the compressed air on the protection valve 12 side with respect to the filter 17 flows back through the filter 17 (the accommodated desiccant) from downstream to upstream, and the regeneration process of the filter 17 is performed.

The operation of the air supply system 10 will be described with reference to fig. 4.

The ECU 80 is provided with a supply start value CI1 corresponding to the air pressure at which the air supply by the compressor 4 is started, and a supply stop value CO corresponding to the air pressure at which the air supply by the compressor 4 is stopped. In addition, a regeneration threshold Cth is set in the ECU 80, the regeneration threshold Cth being a value smaller than the supply stop value CO and higher than the supply start value CI. For example, the supply stop value CO, the supply start value CI, and the regeneration threshold Cth may be stored in a nonvolatile storage portion or the like of the ECU 80. The ECU 80 can measure the period of the regenerative operation using a timer.

In fig. 4, at the timing when the vehicle speed is decreasing, it may be determined that the engine is in no-load operation such as when no fuel injection is performed. Further, at the timing when the brake opening degree is large, it may be determined that the engine is in no-load operation such as when no-fuel injection is performed. The state of the compressor 4 is also linked to the action of the air dryer 11. When the state of the compressor 4 is "stop", the air dryer 11 performs a purge operation, when the state of the compressor 4 is "regeneration", the air dryer 11 performs a regeneration operation, when the state of the compressor 4 is "normal", the air dryer 11 performs a supply operation, and when the state of the compressor 4 is "regeneration", the air dryer 11 also performs a supply operation. In addition, the supply operation is started under the condition that the air pressure is equal to or lower than the supply start value CI. In particular, the operation started when the air pressure is higher than the supply start value CI under the condition that the predetermined condition is satisfied is referred to as the refresh operation. Here, the prescribed conditions are as follows: the air dryer 11 does not perform the regenerating operation, and detects that the air pressure is equal to or lower than the regeneration threshold Cth that is higher than the supply start value CI and lower than the supply stop value CO, and the engine that drives the compressor 4 is in the no-load operation. Wherein the engine is in no-load operation including no-fuel injection of the engine.

The ECU 80 compares the detected air pressure, which is the air pressure detected by the pressure sensor 65, with the supply start value CI. When the detected air pressure becomes equal to or lower than the supply start value CI (time t 0), the ECU 80 switches the air dryer 11 to the supply operation to supply the compressed air to the air tank 13. Thereby, the regulator 26 of the air dryer 11 closes the valve to stop the output of the unloading signal. The compressor 4 is operated under load in response to the stop of the unloading signal. The detected air pressure for the air tank 13 rises (time t0 to time t 1) due to the continuous supply action of the air dryer 11.

When the air pressure detected by the supply of compressed air becomes equal to or higher than the supply stop value CO (time t 1), the ECU 80 switches the air dryer 11 to the regenerating operation. Thus, the regulator 26 opens the valve in the air dryer 11 to output an unloading signal. The compressor 4 is operated without load according to the input of the unloading signal. In addition, in the air dryer 11, the regulator 26 outputs an unloading signal to the drain discharge valve 25. The drain discharge valve 25 is opened in response to input of an unloading signal, and air in the filter 17 of the air dryer 11 flows in the regeneration direction. The regeneration direction is a direction from downstream to upstream, and is a direction opposite to a supply direction of the flow of air when the air is purified. As a result, during a predetermined period, the impurities captured by the filter 17 are discharged as a drain from the drain discharge valve 25 together with the air flowing in the regeneration direction, and the filter 17 is regenerated (time t1 to time t 2).

In addition, when the filter 17 is regenerated in this way, the compressor 4 is operated without load according to the input of the unloading signal, so that the compressed air is not consumed in vain.

In the regeneration operation, the air pressure decreases (time t1 to time t 2) in accordance with the regeneration operation of the compressed air and the consumption of the brake chamber 15. When the regeneration operation is finished, the ECU 80 switches the air dryer 11 to the purge operation. Accordingly, the air pressure of the air tank 13 decreases (time t2 to time t 3) in accordance with the consumption of the compressed air by the brake chamber 15 without flowing through the filter 17.

In the present embodiment, in the non-supply operation, ECU 80 starts the regeneration operation based on satisfaction of the regeneration operation start condition (time t 3). The regeneration action start conditions include: the air dryer 11 does not perform the regenerating operation, and detects that the air pressure is equal to or lower than the regeneration threshold Cth, and detects that the engine driving the compressor 4 is in the no-load operation. For example, at time t3, the vehicle speed is falling, and no-load operation of the engine is detected.

ECU 80 continues the regeneration operation for a predetermined period (time t3 to time t 4). Switching between the load operation and the no-load operation in a short time is avoided in a predetermined period during which the regenerative operation is continued, whereby the application of a high load to the compressor can be avoided. The predetermined period is, for example, a period of 10 seconds. Therefore, the regeneration operation is continued even when the engine is switched to the load operation in the middle of a predetermined period from the start of the regeneration operation. After the predetermined period, ECU 80 stops the regenerating operation according to the engine being in the load operation or the like (time t 4).

When the regeneration operation is completed, the ECU 80 switches the air dryer 11 to the purge operation, as in the case of the regeneration operation. Accordingly, the air pressure of the air tank 13 decreases (time t4 to time t 5) in accordance with the consumption of the compressed air by the brake chamber 15 without flowing through the filter 17.

When the time t5 is reached, the ECU 80 detects that the detected air pressure has become equal to or lower than the supply start value CI, and performs the supply operation (time t5 to time t 6). In addition, ECU 80 stops the supply operation and starts the regeneration operation based on the detected air pressure becoming the supply stop value CO (time t 6). In the regeneration operation, the air pressure decreases (time t6 to time t 7) in accordance with the regeneration operation of the compressed air and the consumption of the brake chamber 15. During the period from time t6 to time t7, the vehicle speed is falling, the engine is in no-load operation, but the air dryer 11 is in regeneration operation. Therefore, even if the air pressure becomes equal to or lower than the regeneration threshold Cth, the regeneration operation is continued (until time t 7).

When the regeneration operation is finished (time t 7), the ECU 80 starts the regeneration operation based on the establishment of the regeneration operation start condition. At this time, ECU 80 continues the regenerative operation based on the fact that the regenerative operation start condition is still satisfied after the predetermined period of time has elapsed. The ECU 80 stops the regeneration operation according to the engine switching to the load operation (time t 8). When the regeneration operation is finished, the ECU 80 switches the air dryer 11 to the purge operation. Accordingly, the air pressure of the air tank 13 decreases (after time t 8) as the compressed air is consumed by the brake chamber 15 or the like.

Various determination processes performed by the ECU 80 in order to perform the regeneration operation will be described in detail with reference to fig. 5 to 11.

As shown in fig. 5, ECU 80 repeats the determination process of the regeneration operation at predetermined intervals. In the determination process of the regenerative operation, the operation determination process (step S10), the suitability determination process (step S11), the signal determination process (step S12), the request determination process (step S13), and the execution determination process (step S14) are sequentially performed.

As shown in fig. 6, the ECU 80 determines whether or not the regeneration operation is possible (i.e., whether or not the regeneration operation is started) in the operation determination process (step S10 of fig. 5) (step S20 of fig. 6). For example, when the vehicle is traveling (the vehicle speed is greater than "0"), the air pressure is higher than the supply start value CI, and three conditions are satisfied, that is, the air dryer 11 is not in the supply operation, the ECU 80 determines that the regeneration operation is possible. Conversely, when at least one of the three conditions of the running state of the vehicle being stopped (the vehicle speed being "0"), the air pressure being equal to or higher than the regeneration threshold Cth, and the air dryer 11 being in the supply operation is established, the ECU 80 determines that the regeneration operation cannot be performed. When the ECU 80 determines that the regeneration operation is possible (yes in step S20 in fig. 6), it sets the operation flag to true (step S21 in fig. 6), and ends the operation determination process. On the other hand, when the ECU 80 determines that the regeneration operation is not possible (no in step S20 in fig. 6), the operation flag is set to false (step S22 in fig. 6), and the operation determination process is terminated.

As shown in fig. 7, ECU 80 determines suitability for the regeneration operation in the suitability determination process (step S11 in fig. 5). The ECU 80 determines whether the engine is in operation (step S30 of fig. 7). For example, ECU 80 determines whether the engine is in operation based on a signal acquired from vehicle ECU 100. Specifically, ECU 80 determines that the engine is in operation based on a signal indicating that the vehicle is running, a signal indicating that the vehicle is stopped, and the like. In contrast, ECU 80 determines that the engine is not in operation based on a signal indicating that the vehicle is in parking.

In addition, the ECU 80 determines whether the engine is in the fuel-free injection (step S31). For example, ECU 80 determines whether the following first condition and second condition are satisfied based on a signal from vehicle ECU 100, and determines that the engine is in the fuel-free injection based on at least one of the first condition and second condition being satisfied. The first condition is related to a fuel injection amount, and includes that a shift operation state is a non-shift operation, and the fuel injection amount is an injection amount threshold or less, and an engine speed is a speed threshold or more. The second condition is independent of the fuel injection amount, and includes that the shift operation state is a non-shift operation, and the accelerator pedal opening is a pedal opening threshold or less, and the engine torque output is a torque output threshold or less, and the engine rotational speed is a rotational speed threshold or more. Here, the rotation speed threshold value is a threshold value for detecting a running state of the vehicle, and is, for example, 700rpm. The pedal opening threshold is a threshold for detecting a no-load state of the engine, for example, 0%. The torque output threshold is a threshold for detecting a no-load state of the engine, for example, 0Nm.

In addition, the ECU 80 determines whether the vehicle (speed) is decelerating (the vehicle speed is decreasing) (step S32). For example, the ECU 80 determines that the vehicle speed is decelerating based on whether at least one of the exhaust brake output being greater than the exhaust brake output threshold and the brake (brake) output being greater than the brake output threshold is established according to a signal from the vehicle ECU 100. Here, the exhaust brake output threshold is a threshold for detecting a brake operating state, and is a value at which a significant brake operation can be detected, for example, 1% to 2%. The deceleration brake output threshold value is a threshold value for detecting a brake operating state, and is a value at which a significant brake operation can be detected, for example, 1% to 2%.

Further, the ECU 80 determines whether the vehicle speed is equal to or greater than a threshold value of the resumable speed (step S33). For example, ECU 80 determines whether the vehicle speed is equal to or higher than the reproducible speed threshold based on comparing a value corresponding to a signal from vehicle ECU 100 with the reproducible speed threshold. Here, the renewable speed threshold is a threshold for detecting a running state of the vehicle, for example, 5km/h.

In addition, the ECU 80 determines whether or not the air pressure of the compressed air is equal to or higher than a regeneration suitable pressure threshold (step S34). For example, the ECU 80 compares the detected air pressure of the pressure sensor 65 with the regeneration proper pressure threshold to determine whether or not the air pressure of the compressed air is equal to or higher than the regeneration proper pressure threshold. Here, the regeneration suitable pressure threshold is a value of pressure required for maintaining a predetermined minimum regeneration supply time, for example, higher than the supply start value CI and lower than the regeneration threshold Cth. When all of the conditions in steps S30 to S34 are satisfied (yes in step S34), the ECU 80 sets the suitability flag to true (step S35), and ends the suitability determination process. On the other hand, when it is determined that any one of the five steps S30 to S34 is not established (no in any one of the steps S30 to S34), the ECU 80 sets the suitability flag to false (step S36), and ends the suitability determination process.

The suitability determination process may be a process based on one or more determinations in steps S31 to S34 in fig. 7.

As shown in fig. 8, in the signal determination process (step S12 of fig. 5), the ECU 80 sets the signal based on the signal associated with the regeneration operation. The ECU 80 determines whether or not the regeneration operation is in progress (step S40 of fig. 8). When determining that the regeneration operation is in progress (yes in step S40), ECU 80 counts the regeneration supply duration timer (step S41). If it is determined that the regeneration operation is not in progress (step S40: NO), the ECU 80 resets the regeneration supply duration timer (step S42).

Further, ECU 80 determines whether or not the retrogradation supply duration timer is a predetermined duration or longer (step S43). The predetermined duration is a duration of the regenerative supply operation, and is set to 10 seconds, for example. When determining that the retrogradation supply duration timer is equal to or longer than the predetermined duration (yes in step S43), the ECU 80 sets the reception flag to true (step S44), and ends the signal determination process. On the other hand, when it is determined that the retrogradation supply duration timer is not longer than the predetermined duration (step S43: no), the ECU 80 sets the reception flag to "false" (step S45), and ends the signal determination process.

As shown in fig. 9, in the request determination process (step S13 in fig. 5), ECU 80 sets a start flag regarding the start request determination of the regenerative operation. The ECU 80 determines whether there is a request for starting the regeneration operation (step S50 of fig. 9). For example, when the condition that the detected air pressure of the pressure sensor 65 is smaller than the supply stop value CO, the reception flag is true, and the suitability flag is true is satisfied, it is determined that a start request is present. If there is a start request (yes in step S50), the ECU 80 sets the start flag to true (step S51). If there is no start request (step S50: NO), the ECU 80 sets the start flag to "false" (step S52).

In addition, the ECU 80 determines whether or not there is a stop request (step S53). For example, in the case where the start flag is "false" and the action flag is "false", ECU 80 determines that there is a stop request. When determining that there is a stop request (yes in step S53), ECU 80 sets the stop flag to true (step S54), and ends the request determination process. On the other hand, when it is determined that there is no stop request (no in step S53), ECU 80 sets the stop flag to "false" (step S55), and ends the request determination process.

As shown in fig. 10, when the resumption supply operation is not performed, the ECU 80 determines whether or not the resumption supply operation is performed (step S60) in the execution determination process (step S14 of fig. 5). The ECU 80 determines that the regenerative supply operation is to be executed based on at least one of the fact that the detected air pressure of the pressure sensor 65 is equal to or lower than the supply start value CI and that the start flag is true. When determining that the resumption supply operation is to be performed (yes in step S60), ECU 80 executes the resumption supply operation (step S61) and ends the execution determination process. On the other hand, when it is determined that the resumption supply operation is not to be performed (step S60: NO), the ECU 80 does not perform the resumption supply operation (step S62) and ends the execution determination process.

As shown in fig. 11, ECU 80 performs a stop determination process when the regenerative supply operation is being executed. In the stop determination process, it is determined whether or not to stop the regeneration supply (step S70). The ECU 80 determines that the regenerative supply is stopped based on the fact that the detected air pressure of the pressure sensor 65 is lower than the supply stop value CO and that the stop flag is true. When determining that the resumption supply is stopped (yes in step S70), ECU 80 stops the resumption supply (step S71) and ends the stop determination process. On the other hand, when it is determined that the resumption supply is not stopped (step S70: no), the ECU 80 ends the stop determination process without stopping the resumption supply (step S72 in fig. 11).

As described above, according to the present embodiment, the following effects can be obtained.

(1) For example, when the vehicle is in a no-load operation in which the engine is driven by rotation of wheels during deceleration, regenerative supply is performed in which compressed air is supplied by driving the compressor 4 by rotation of the engine. The regeneration supply is performed before the supply of the compressed air by the normal supply operation, and the supply of the compressed air by the normal supply operation is supplemented. In addition, in the regeneration supply, fuel consumption for driving the compressor 4 does not occur in the engine, so that the combustion consumption rate of the engine can be improved.

(2) When the engine is in a fuel-free injection, the rotation of the engine is effectively utilized for the air supply.

(3) When the compressor 4 is switched from the no-load operation to the load operation by continuing the regeneration supply for 10 seconds or longer, the occurrence of timing when the compressed air is not supplied due to the delay in the supply of the compressed air can be avoided.

(4) Since the regeneration supply is performed on the condition that the regeneration threshold Cth is equal to or smaller than the regeneration threshold Cth, it is possible to suppress the detected air pressure from reaching the supply stop value CO during the regeneration supply.

(5) The condition that the engine is in no-load operation can be obtained from the control device of the vehicle.

The present embodiment can be modified and implemented as follows. The present embodiment and the following modifications can be combined and implemented within a range that is not technically contradictory.

The air tank 13 may supply compressed air to devices consuming compressed air other than the brake valve 14, for example, a parking brake.

The pressure sensor 65 can detect the air pressure at any position downstream of the check valve 19 as long as it can detect the air pressure corresponding to the air pressure of the air tank 13. For example, the pressure sensor may also detect the air pressure within the air tank. Thus, the supply operation, the non-supply operation, the regeneration operation, and the regeneration operation may be controlled based on the detected air pressure in the air tank.

In the above embodiment, the filter 17 has both the desiccant and the filter unit, but the filter 17 may have only one of them.

In the above embodiment, the case where the filter 17 is provided is exemplified, but the present invention is not limited to this, and an oil mist separator may be provided upstream of the filter 17.

The oil mist separator includes a filter that performs gas-liquid separation by colliding with the compressed air, and captures oil contained in the compressed air sent from the compressor 4. The filter may be formed by compression molding a metal material, or may be a porous material such as a sponge. By providing the oil mist separator, the purification performance of the compressed air can be further improved.

The regeneration supply may not be started when the regeneration operation is being performed. In this way, the regenerating operation does not become wasteful due to the regenerative supply. In addition, the regenerative supply does not become wasteful due to the regenerating operation.

The regeneration operation may not be started when the regeneration supply is being performed. For example, when the regeneration supply is continued for a predetermined period, the regeneration operation may not be started until the predetermined period of the regeneration supply is completed even if the air pressure reaches the supply stop value CO. In this way, the regenerative supply does not become wasteful due to the regenerating operation. In addition, the regeneration performance is not reduced due to the interruption of the regeneration operation caused by the regeneration supply.

In the above embodiment, the description has been made assuming that the air supply system 10 is mounted on an automobile such as a truck, a bus, or a construction machine. As another aspect, the air supply system may be mounted on another vehicle such as a car or a railway vehicle.

Description of the reference numerals

4: a compressor; 10: an air supply system; 11: an air dryer; 11A: an inner space; 12: a protection valve; 13: a gas tank; 14: a brake valve; 4E, 11E, 12E, 13E, 14E: an air supply path; 15: a brake chamber; 16: a branching path; 17: a filter; 18: an air supply passage; 19: a one-way valve; 20: a bypass flow path; 21: a regeneration control valve; 22: an orifice; 25: a liquid discharge valve; 26: a regulator; 27: a liquid discharge outlet; 65: a pressure sensor; 66: a temperature and humidity sensor; 80: an ECU;100: a vehicle ECU; e62, E63, E65, E66: wiring; p12: maintenance ports.

Claims

1. An air supply system for performing a supply operation of supplying compressed air supplied from a compressor from an upstream to a downstream via an air dryer having a filter and a check valve, the air supply system comprising:

a pressure sensor that detects an air pressure downstream of the check valve; and

a control device that switches between the supply operation and a non-supply operation, and performs a regeneration operation for regenerating the filter during the non-supply operation,

wherein the control device includes a supply start value for starting the supply operation based on a comparison of the supply start value and a detected air pressure detected by the pressure sensor, and a supply stop value higher than the supply start value for starting the non-supply operation based on a comparison of the supply stop value and the detected air pressure,

the control device also performs the supply action by regenerating the supply if a condition is satisfied that includes: the regeneration action is not performed; the detected air pressure is higher than the supply start value and lower than the supply stop value; and the engine driving the compressor is in no-load operation.

2. An air supply system according to claim 1, wherein,

the no-load operation of the engine includes when no fuel injection of the engine is performed.

3. An air supply system according to claim 1 or 2, characterized in that,

the control device causes the retrogradation supply to last for 10 seconds or longer.

4. An air supply system according to any one of claims 1 to 3, wherein,

the condition further includes that the detected air pressure is equal to or lower than a predetermined air pressure.

5. An air supply system according to any one of claims 1 to 4, characterized in that,

when the regenerating operation is being performed, the control device does not start the regenerating supply.

6. An air supply system according to any one of claims 1 to 5, characterized in that,

the control device acquires, from a control device of a vehicle, a case where the engine is in no-load operation.